Detectable heavy duty needle

ABSTRACT

The present invention provides a detectable heavy duty needle cannula ( 12 ) for use in hypodermic syringes and the like. Needle cannula ( 12 ) comprises a magnetizable or magnetized stainless steel alloy, which enables needle cannula ( 12 ) to be detectable in metal detectors that are commonly used in the meat processing industry to detect broken needle cannulas in the flesh of slaughtered animals. Needle cannula ( 12 ) further comprises a sidewall ( 17 ) that is thicker than the sidewalls of prior art needle cannulas. The thicker sidewall imparts to needle cannula ( 12 ) greater resistance to breakage during the process of injecting animal health products into an animal and greater detectability in a metal detector.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] Not Applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not Applicable.

BACKGROUND OF THE INVENTION

[0003] (1) Field of the Invention

[0004] The present invention relates to a detectable heavy duty needlecannula for use in hypodermic syringes and the like. The needle cannulacomprises a magnetized stainless steel alloy, which enables the needlecannula to be detectable in metal detectors that are commonly used inthe meat processing industry to detect broken needle cannulas in theflesh of slaughtered animals. The needle cannula further comprises asidewall that is thicker than prior art needle cannulas. The thickersidewall imparts to the needle cannula greater resistance to breakageduring the process of injecting animal health products into an animaland greater detectability in a metal detector.

[0005] (2) Description of Related Art

[0006] Stainless steel alloys are extensively used in manufacturingneedle cannulas for hypodermic syringes for injecting animal healthproducts into animals. From time to time, when these needles are used tovaccinate an animal, particularly the large domestic animals used formeat production, a part of the needle cannula breaks off and remainslodged within the flesh of the animal. Because meat containing a brokenpiece of needle is unfit for human consumption, any meat that contains abroken needle must be separated from the meat that is safe for humanconsumption.

[0007] The meat processing industry uses metal detectors to detectbroken needles lodged within the flesh of the animal. However, becausethe needle cannulas used for veterinary purposes are made fromnon-magnetic stainless steel alloys, they are difficult to detect withthe metal detectors that are used in the meat processing industry.Detection is particularly difficult when the needle's length to diameterratio is low because at such low ratios the orientation of the needle inthe meat affects detectability.

[0008] In order to improve detection of these needles, the metaldetectors are routinely operated at high sensitivity levels. However, atsensitivity levels the frequency of false positives is increased.Therefore, a greater proportion of meat than is necessary is culled.

[0009] Therefore, there is a need for a needle cannula that is moreresistant to breakage during the process of injecting animal healthproducts into an animal. There is also a need for a needle cannula thatcan be readily detected in the metal detectors that are commonly used inthe meat processing industry to detect broken needle cannula in theflesh of animals after slaughter.

SUMMARY OF THE INVENTION

[0010] The present invention provides a detectable heavy duty needlecannula for use in hypodermic syringes and the like. The needle cannulacomprises a magnetic stainless steel alloy, which enables the needlecannula to be detectable in a metal detector. Particularly in the metaldetectors that are commonly used in the meat processing industry todetect broken needle cannulas in the flesh of slaughtered animals. Theneedle cannula further comprises a sidewall that is thicker than priorart needle cannulas, which imparts to the needle cannula greaterresistance to breakage during the process of injecting animal healthproducts into an animal and increases its detectability in a metaldetector.

[0011] The present invention provides a needle assembly comprising anelongate permanently magnetizable or magnetic stainless steel needlecannula having a proximal end, a distal end and a sidewall therebetween,the cannula having a lumen therethrough wherein the cannula at itsproximal end is securely fixed to a mounting hub which is capable ofbeing mounted on a device for injecting a dosage of a material in ananimal. In particular, a needle assembly for use in a hypodermic needleand the device is a hypodermic syringe. Preferably, the sidewall has athickness greater than 0.46 mm, in particular when the lumen has adiameter of about 1.19 mm. In a preferred embodiment, the needle cannulahas a circular cross-section and the mounting hub includes projectionsextending therefrom for threaded engagement with a luer collar.

[0012] The present invention also provides a stainless steel tubularneedle defined by at least one wall forming the tube and supported on ahub for mounting on a device for injecting a dosage of a material in ananimals, wherein the needle is magnetizable or magnetic to a level whichenables detection of the magnetism of the needle when broken off in theflesh of an animal when the animal is slaughtered and processed.Preferably, the needle is a hypodermic needle and wherein the materialis a fluid. It is further preferable that the wall have a thickness ofgreater than 0.018 inch and an inside diameter of about 0.046 inch. Itis preferable further still that the needle have a circularcross-section.

[0013] The present invention also provides a method of injecting fleshof a living food animal which comprises (a) providing an injection meanscomprising a tubular needle defined by at least one wall forming thetube and supported on a hub and mounted on a device for injecting adosage of a material in an animal, wherein the needle is made ofstainless steel, which is magnetizable or magnetic at a level thatenables detection of the magnetism of the needle if the needle is brokenoff in the flesh of the living animal during the injection; and (b)injecting the living animal with the dosage using the needle, wherebywhen the needle breaks in the animal during the injection, the needlecan be detected in the flesh of the animal upon slaughter and processinginto the food.

[0014] The present invention further provides in a slaughtering methodfor slaughter and processing of animals for food while conveying theflesh of the animal, the improvement which comprises detecting a brokenstainless steel tubular needle in the flesh, wherein the needle has atleast one wall and is supported on a hub for mounting on a device forinjecting a dosage of a material into an animal, wherein the needle ismagnetized to a level which enables detection of the magnetism of theneedle when broken off in the flesh of an animal when the animal isslaughtered and processed. In the foregoing methods it is preferablethat the needle be a hypodermic needle. Particularly, a needle whereinthe wall has a thickness of greater than 0.018 inch, and further,wherein the needle has an inside diameter of about 0.046 inch. Themethod is particularly useful when the animal is a swine.

[0015] In either of the above methods, the needle can be the abovepermanently magnetizable or magnetic stainless steel needle cannulahaving a proximal end, a distal end and a sidewall therebetween, thecannula having a lumen therethrough defining a cannula longitudinal axiswherein the cannula at its proximal end is securely fixed to a mountinghub which is capable of being mounted on a device for injecting a dosageof a material in an animal.

[0016] In any one of the aforementioned embodiments of the presentinvention, the stainless steel comprises Fe and 0.01-3.0 wt % Si, lessthan 0.03 wt % P, 4-25 wt % Cr, 0.003-7.0 wt % Al, 0.01-1.0 Mn,0.001-0.03 wt % S, 0.01-5.0 wt % Mo, 0.01-1.0 wt % Ti, 0.003-0.08 wt %C, 0.01-5.0 wt % Ni, 0.01-0.5 wt % Cu, less than 0.01 wt % Pb, 0.02-0.5Bi, 0.5-1.0 wt % Nb, 0.02-1.0 wt % Zr, and 0.05-1.0 wt % V. Preferably,a stainless steel alloy comprising Fe and 0.36 wt % Si, 0.20 wt % P,24.68 wt % Cr, 0.01 wt % Al, 0.90 wt % Mn, 0.009 wt % S, 1.80 wt % Mo,less than 0.01 wt % Ti, 0.08 wt % C, 4.98 wt % Ni, 0.10 wt % Cu, andless than 0.01 wt % Pb.

[0017] Therefore, it is an object of the present invention to provide aneedle cannula that is more resistant to breakage during the process ofinjecting animal health products into an animal.

[0018] It is also an object of the present invention to provide a needlecannula comprising a stainless steel alloy that is magnetized tofacilitate detection of the broken needle cannula in the flesh of theanimal using the metal detectors that are commonly used in the meatprocessing industry.

[0019] These and other objects will become increasingly apparent withreference to the following descriptions and the drawings.

DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 is a longitudinal cross-sectional view of the needleassembly comprising the detectable heavy duty needle of the presentinvention.

[0021]FIG. 2 is an isometric view of the detectable heavy duty needle ofthe present invention.

[0022]FIG. 3 is a perspective view of an apparatus comprising a metaldetector for detecting a part of the detectable heavy duty needle of thepresent invention broken off in the flesh of an animal and a conveyorfor transporting the flesh through the metal detector.

DETAILED DESCRIPTION OF THE INVENTION

[0023] All patents, patent applications, government publications,government regulations, and literature references cited in thisspecification are hereby incorporated herein by reference in theirentirety. In case of conflict, the present description, includingdefinitions, will control.

[0024] The present invention provides a detectable heavy duty needlecannula for use in hypodermic syringes, catheters, and the like. Theneedle cannula comprises a magnetized stainless steel alloy, whichenables the needle cannula or broken pieces of the needle cannula in theflesh of an animal to be detected in a metal detector regardless of theorientation of the broken piece in the flesh. Preferably, the needlecannula comprises a permanently magnetized stainless steel alloy. Thepresent invention is particularly useful to the meat processing industrybecause it enables broken needle cannulas in the flesh of slaughteredanimals to be detected using the metal detectors already being used. Thepresent invention does not require the meat processing industry topurchase new metal detectors. The needle cannula of the presentinvention further comprises a sidewall that is thicker than prior artneedle cannulas, which imparts to the needle cannula greater resistanceto breakage during the process of injecting animal health products intoan animal.

[0025] Thus, the needle cannula of the present invention is moreresistant to breakage than the thinner prior art needles and because ofboth its thickness and magnetizability it is easier to detect a brokenpiece of the needle in the flesh of an animal during processing of theanimal after slaughter. Furthermore, the needle cannula of the presentinvention is magnetizable while still comprising a stainless steelalloy, which makes it acceptable for administering animal healthproducts to an animal.

[0026]FIG. 1 schematically illustrates a needle assembly 10 adapted fordetachably mounting on a luer collar of a hypodermic syringe or the likecomprising the detectable heavy duty needle cannula 12 having proximalend 14, distal end 16, and a sidewall 17 with an outer sidewall 17A andinner sidewall 17B therebetween having a lumen 18 extending therethroughdefining a longitudinal axis. Distal end 16 of the needle cannula 12preferably includes sharpened tip 20. A mounting hub 22 is securelyaffixed to the proximal end 14 of needle cannula 12 and includesprojections 24 extending therefrom for threaded engagement with a luercollar or like attachment means. Thus, needle assembly 10 is mountableon a hand-held hypodermic syringe barrel. However, needle assembly 10can also be mounted on a catheter device or mounted on automaticinjection devices.

[0027] The mounting hub 22, preferably metal such as a stainless steelalloy or brass alloy or molded polypropylene plastic or the like, iscomprised of a main body section 26 which has a means for fixedlyretaining needle cannula 12 associated therewith and an axiallyextending rigid wall section 28 adapted for detachably engaging ahypodermic syringe outlet (not shown). The mounting hub 22 has an axialpassage 30 which extends longitudinally through the end walls ofmounting hub 22. The distal portion 32 of axial passage 30 preferablyhas a diameter slightly larger than the outer diameter of a maledischarge outlet of a syringe on which the needle assembly 10 is adaptedto be mounted. The outer surface 34 of mounting hub 22 can be providedwith flat surfaces to serve as gripping means to facilitate mountingneedle assembly 10 on an outlet of a hypodermic syringe or the like.Alternatively, mounting hub 22 can be provided with one or more radiallyextending projections to serve as the gripping means.

[0028] As shown in FIG. 2 in greater detail, needle cannula 12 istubular with proximal end 16, distal end 14, and a sidewall 17therebetween. The needle cannula 12 has a lumen 18 defining a cannulalongitudinal axis 19. Preferably, needle 12 has a sharpened tip 20 atdistal end 16 and is blunt at proximal end 14. In the case of the 16gauge embodiment of the needle of the present invention, the sidewall 17has a thickness greater than 0.46 mm (0.018 inch), preferably athickness of 0.64 mm (0.025 inch) and the diameter of lumen 18 is about1.19 mm (0.047 inch). Thus, the outer diameter of needle 12 is about 1.8mm (0.072 inch). Preferably, the needle cannula of the present inventionhas a circular cross-section. In contrast, a 16 gauge prior art needlehas an outside diameter of about 1.65 mm (0.065 inch) and a lumendiameter of about 1.19 mm (0.047 inch). Therefore, the wall of the priorart needle is about 0.46 mm (0.018 inch), which is somewhat more likelyto break. Also, because the prior art needle cannula has a smallerdiameter, a broken piece of the prior art needle cannula is lessdetectable. FIG. 1 shows a particular embodiment of needle assembly 10comprising needle cannula 12; however, the detectable needle cannula ofthe present invention is not limited to that particular embodiment. Aswould be apparent to one skilled in the art, needle cannula 12 cancomprise other needle assembly embodiments such as the needle assemblyembodiments shown in U.S. Pat. RE No. 28,713 to Stevens et al. and U.S.Pat. No. 6,027,482 to Imbert.

[0029] While the 16 gauge embodiment is shown herein, the needle cannulaof the present invention includes needle cannulas of other gauges andneedle assemblies comprising needle cannulas of other gauges. Forexample, needle cannulas that are useful for medical and veterinarianpurposes generally include those gauges within the range 14 to 26. Thus,the needle cannula of the present invention includes, but is not limitedto, gauges between 14 and 27. It should be understood that because thesidewall of the needle cannula of the present invention is thicker thanthe sidewall of prior art needle cannulas and the outer diameter of theneedle cannula determines the gauge, a 16 gauge needle cannula of thepresent invention has an outer diameter similar to the outer diameter ofa 15 gauge needle cannula.

[0030] The detectable heavy duty needle cannula of the present inventioncomprises a magnetized stainless steel alloy. The stainless steel alloycan comprise any corrosion-resistant magnetic material with an elementalcomposition within the range set forth in U.S. Pat. No. 5,601,644 toKosa et al and U.S. Pat. No. 4,969,963 to Honkura et al. In general, themagnetized stainless steel comprises 0.01-3.0 wt % Si, less than 0.03 wt% P, 4-25 wt % Cr, 0.003-7.0 wt % Al, 0.01-1.0 Mn, 0.001-0.03 wt % S,0.01-5.0 wt % Mo, 0.01-1.0 wt % Ti, 0.003-0.08 wt % C, 0.01-5.0 wt % Ni,0.01-0.5 wt % Cu, less than 0.01 wt % Pb, and the remainder Fe.Preferably, instead of Pb, the magnetized stainless steel comprises0.02-0.5 Bi. Preferably, the magnetic stainless steel further comprises0.5-1.0 wt % Nb, 0.02-1.0 wt % Zr, and 0.05-1.0 wt % V, which improvethe toughness and magnetic properties of the stainless steel. In apreferred embodiment, the magnetized stainless steel comprises, based ona chemical test where the test results conform to UNS S32900, 0.36 wt %Si, 0.20 wt % P, 24.68 wt % Cr, 0.01 wt % Al, 0.90 wt % Mn, 0.009 wt %S, 1.80 wt % Mo, less than 0.01 wt % Ti, 0.08 wt % C, 4.98 wt % Ni, 0.10wt % Cu, and less than 0.01 wt % Pb. The remainder comprises Fe.

[0031] Thus, the preferred stainless steel alloy is an alloy that ispermanently magnetic or magnetizable before detection. The magneticalloy is detectable using the metal detectors that are commonly used inthe meat processing industry. Thus, the meat processing industry doesnot need to purchase new equipment for detecting the needle cannulas ofthe present invention or pieces thereof in the flesh of animals or theirmeat products. However, the present invention is not limited to needlecannulas comprising stainless steel alloys that are permanent magnets.

[0032] Alternatively, the needle cannula of the present invention cancomprise a stainless steel alloy that is not a permanent magnetic but iscapable of being magnetized in a magnetic field to maintain a residualmagnetism. When the alloy is subjected to a high magnetic field,preferably of an intensity equivalent to or greater than required forimparting saturated magnetization, the alloy acquires a residualmagnetism that persists when the magnetic field is removed. Thus, aneedle cannula or piece thereof comprising a residual magnetism, whichis embedded in the flesh of an animal or meat product, can be detectedin a metal detector or magnetic detector comprising Hall elements thatutilize the Hall effect, coils for detecting a static magnetic field,magnetoresistance (MR) effect elements, or magnetic impedance (MI)effect elements. An example of using a magnetic detector for detectingmagnetized substances in a non-magnetic product while not detectingnon-magnetizable metal is disclosed in U.S. Pat. No. 5,923,165 to Horitaet al. However, a magnetic detector is limited to detecting magnetizedmetals. It cannot detect non-magnetizable metals such as aluminum,copper, lead, non-magnetizable stainless steel, brass, and cast zinc.Since non-magnetizable metals from a plurality of sources can be presentin the flesh of an animal during processing after slaughter, it ispreferable that the detection means be able to detect both magnetizableand non-magnetizable metals in the flesh of an animal. Therefore, ametal detector is preferred. Thus, the detectable heavy dutymagnetizable needle cannula of the present invention is compatible withmetal detectors that detect both magnetizable and non-magnetizablemetals such as aluminum, copper, lead, non-magnetizable stainless steel,brass, and cast zinc.

[0033]FIG. 3 shows one embodiment for an apparatus for detecting metalin the flesh of an animal after slaughter. Shown is apparatus 100comprising a conveyor means 102 for transporting animal flesh or meatproducts after slaughter 200 through metal detector 104 for detectingwhether animal flesh contains a broken piece of needle cannula 12 of thepresent invention. Metal detector 104, comprises a coil arrangement 110(shown in FIG. 4) inside a metal case 106. This metal detectorembodiment is one that is commonly used in the meat processing industryto detect metal in animal flesh after slaughter. The metal detector 104can be operably connected to a control unit (not shown) to signal whenthe animal flesh contains a broken part of the needle cannula of thepresent invention. The control unit can comprise a computer processingunit. The apparatus 100 can further comprise a means for removing fromconveyor animal flesh or meat products after slaughter that contain abroken piece of the needle cannula of the present invention.Alternatively, apparatus 100 comprises a means for marking animal fleshor meat products after slaughter that contain the needle cannula of thepresent invention for removal from conveyor means 102 either manually ormechanically. In particular embodiments, apparatus 100 can furthercomprise a means for producing a high magnetic field (not shown) tomagnetize or enhance the magnetism of the stainless steel comprisingneedle cannula 12 or piece thereof in animal flesh or meat product afterslaughter 200 before it enters metal detector 104. This improves thedetectability of the metal.

[0034] The metal detector preferably uses a balanced three-coil system110 (FIG. 4), which is a configuration that is commonly used in themetal detectors used in the meat processing industry to detect metal inthe flesh of animals after slaughter. The three coils are wound on anon-metallic frame or former, each exactly parallel with the other. Thecenter transmitter coil 112 is connected to a high frequency radiotransmitter. The two receiver coils 114 on each side of coil 112 act asradio receivers or aerials. Because receiver coils 114 are identical andthe same distance to transmitter coil 112, they pick up the same signaland an identical voltage is induced in each. When coils 114 areconnected in opposition, they cancel out resulting in zero output.

[0035] When a piece of metal in animal flesh or meat product afterslaughter 210 passes through coil arrangement 110, the high frequencyfield is disturbed under one coil, changing the voltage generated by afew microvolts. The perfect state of balance is lost and the output isno longer zero. The resulting signal output is sent to a receiver whereit is processed and amplified. The processed signal is then sent to acomputer processing unit or other device. It is this frequencydisturbance phenomenon that is used to detect the presence of unwantedmetal in the flesh of an animal after slaughter. A magnetized ormagnetic piece of metal will also induce a change in voltage that can bemeasured by the metal detector.

[0036] Preferably, coil arrangement 110 is mounted inside a metal case106 with a hole in the center to allow passage of animal flesh or meatproduct after slaughter 200 (FIG. 3). Metal case 106 provides rigidityto coil arrangement 110 and acts as a screen, preventing preventairborne electrical signals, or nearby metal items and machinery fromdisturbing the detector. Aluminum is frequently used for metal case 106but where frequent washdown is required such as in meat processingplants, stainless steel is generally used.

[0037] When a non-spherical particle such as a part of a needle cannulapasses through metal detector 104, it will be easier to detect in oneorientation than in another. In the case of a linear non-ferrousarticle, the article is easily detected when the orientation of thearticle is perpendicular to its flow through the detector and difficultto detect when it is orientated parallel to the direction of flowthrough the detector. The converse is true for ferrous linear articles.However, this orientation effect is generally only evident when thediameter of the object is less than the spherical sensitivity of themetal detector. For example, when the sensitivity of the detector is setat 1.5 mm (0.06 inch) diameter, only articles thinner than 1.5 mm willshow the orientation effect. Increasing the sensitivity to 1.0 mm, onlyarticles thinner than 1.0 mm (0.04 inch) will show the orientationeffect. But the ability to detect thin linear articles independent oforientation is very dependent on the composition of the article.

[0038] In general, linear non-magnetized ferrous articles with adiameter of 0.95 mm (0.037 inch), the minimum length to guaranteedetectability at a sensitivity of 1.2 mm independent of orientationeffects is 1.5 mm (0.06 inch). At a sensitivity of 1.5 mm, the minimumlength that is guaranteed detectable is 3.0 mm (0.12 inch); at asensitivity of 2.0 mm (0.08 inch), the minimum length is 6 mm (0.24inch); and, at a sensitivity of 2.5 mm (0.1 inch) the minimum lengththat is guaranteed detectable is 11.0 mm (0.44 inch).

[0039] In contrast, a linear non-magnetized stainless steel article witha diameter of 1.60 mm (0.063 inch), the minimum length to guaranteedetectability at a sensitivity of 1.5 mm independent of orientationeffects is 8.0 mm (0.31 inch). At a sensitivity of 2.0 mm, the minimumlength that is guaranteed detectable is 24 mm (0.96 inch), and at asensitivity of 2.5 mm, the minimum length that is guaranteed detectableis 64.0 mm (2.52 inch). However, at a sensitivity of 1.2 mm, a stainlesssteel article with a diameter of 1.6 mm is not detectable independent oforientation effects. Thus, it is much more difficult to guaranteedetection of a stainless steel article than a ferrous article. Theorientation effect is of particular significance in the meat processingindustry because the orientation of a broken stainless steel needlecannula in the flesh of the meat from an animal is unknown.

[0040] While the sensitivity of the metal detector can be increased inorder to detect short articles of small diameter, other problems becomemanifest. For example, as sensitivity is increased, the problems ofdrift become more acute and the number of false rejects can increase toan unacceptable level. Also, wet products such as meat products createan interference signal in the detector, which must be canceled out. Thistends to reduce the sensitivity of the detector. To minimize the effect,a lower operating frequency is often selected in the range of 10 to 50KHz. This reduces the interference signal from the wet product but alsoreduces the sensitivity of the detector, particularly as it pertains tostainless steel.

[0041] Thus, in order to detect a length of a stainless steel 16 gaugeprior art needle cannula, which has a diameter of about 1.65 mm, thelength of needle that is embedded in the flesh of the animal must be atleast about 8 mm to be detected free of orientation effects at asensitivity of 1.5 mm or at least about 24 mm to be detected free oforientation effects at a sensitivity of 2.0 mm. The standard 16 gaugeneedle used for injecting animal health products into an animal is about19.0 mm in length.

[0042] In contrast, the length of the magnetized heavy duty stainlesssteel needle cannula of the present invention that can be detected freeof orientation effects at a sensitivity of 1.5 mm and 2.0 is about 7.0mm and 21.0 mm, respectively. Furthermore, because the needle ismagnetic, the length of the needle that is detectable free oforientation effects is shorter still. Thus, the magnetic heavy dutystainless steel needle cannula of the present invention can be detectedfree of orientation effects at a sensitivity that is about equivalent tothe detectability of a linear ferrous article. Therefore, the detectableheavy duty needle of the present invention reduces the risk that a meatproduct containing a part of a broken needle cannula will escapedetection.

[0043] The apparatus 100 can comprise one or more magnetic detectorsdisposed over the conveyor such as those comprising Hall elements,coils, MR effect elements, or MI effect elements. When a piece ofmagnetized metal passes through Hall elements or coils it causes ameasurable variation in voltage, when it passes through MR effectelements it causes a measurable variation in resistance, and when itpasses through MI effect elements it causes a measurable variation inresistance. The measurable variation produces a signal that is sent to acontrol unit as above, which directs the removal of the meat containingthe magnetized metal. While a magnetic detector can be the soledetection means in the apparatus, it is preferable that the apparatuscomprise a metal detector to enable detection of non-magnetizablemetals. An apparatus comprising solely a magnetic detector is limited todetecting magnetic metals or metals that can be magnetized to possess aresidual magnetism.

[0044] While the present invention is described herein with reference toillustrated embodiments, it should be understood that the invention isnot limited hereto. Those having ordinary skill in the art and access tothe teachings herein will recognize additional modifications andembodiments within the scope thereof. Therefore, the present inventionis limited only by the claims attached herein.

I claim:
 1. A needle assembly comprising an elongate permanently magnetizable or magnetic stainless steel needle cannula having a proximal end, a distal end and a sidewall therebetween, the cannula having a lumen therethrough wherein the cannula at its proximal end is securely fixed to a mounting hub which is capable of being mounted on a device for injecting a dosage of a material in an animal.
 2. The needle assembly of claim 1 wherein the assembly is for use in a hypodermic needle and the device is a hypodermic syringe.
 3. The needle assembly of claim 1 or 2 wherein the sidewall has a thickness greater than 0.46 mm.
 4. The needle assembly of claim 3 wherein the lumen has a diameter of about 1.19 mm.
 5. The needle assembly of claim 1 wherein the magnetic stainless steel comprises Fe and 0.01-3.0 wt % Si, less than 0.03 wt % P, 4-25 wt % Cr, 0.003-7.0 wt % Al, 0.01-1.0 Mn, 0.001-0.03 wt % S, 0.01-5.0 wt % Mo, 5 0.01-1.0 wt % Ti, 0.003-0.08 wt % C, 0.01-5.0 wt % Ni, 0.01-0.5 wt % Cu, less than 0.01 wt % Pb, 0.02-0.5 Bi, 0.5-1.0 wt % Nb, 0.02-1.0 wt % Zr, and 0.05-1.0 wt % V.
 6. The needle assembly of claim 5 wherein the magnetic stainless steel comprises Fe and 0.36 wt % Si, 0.20 wt % P, 24.68 wt % Cr, 0.01 wt % Al, 0.90 wt % Mn, 0.009 wt % S, 1.80 wt % Mo, less than 0.01 wt % Ti, 0.08 5 wt % C, 4.98 wt % Ni, 0.10 wt % Cu, and less than 0.01 wt % Pb.
 7. The needle assembly of claim 1 wherein the needle cannula has a circular cross-section.
 8. The needle assembly of claim 1 wherein the mounting hub includes projections extending therefrom for threaded engagement with a luer collar.
 9. A stainless steel tubular needle defined by at least one wall forming the tube and supported on a hub for mounting on a device for injecting a dosage of a material in an animals, wherein the needle is magnetizable or magnetic to a level which enables detection of the magnetism of the needle when broken off in the flesh of an animal when the animal is slaughtered and processed.
 10. The needle of claim 9 which is a hypodermic needle and wherein the material is a fluid.
 11. The needle of claim 9 or 10 wherein the wall has a thickness of greater than 0.018 inch.
 12. The needle of claim 11 wherein the needle has an inside diameter of about 0.046 inch.
 13. The needle of claim 1 wherein the stainless steel comprises Fe and 0.01-3.0 wt % Si, less than 0.03 wt % P, 4-25 wt % Cr, 0.003-7.0 wt % Al, 0.01-1.0 Mn, 0.001-0.03 wt % S, 0.01-5.0 wt % Mo, 0.01-1.0 wt % Ti, 0.003-0.08 wt % C, 0.01-5.0 wt % Ni, 0.01-0.5 wt % Cu, less than 0.01 wt % Pb, 0.02-0.5 Bi, 0.5-1.0 wt % Nb, 0.02-1.0 wt % Zr, and 0.05-1.0 wt % V.
 14. The needle of claim 13 wherein the stainless steel contains Fe and 0.36 wt % Si, 0.20 wt % P, 24.68 wt % Cr, 0.01 wt % Al, 0.90 wt % Mn, 0.009 wt % S, 1.80 wt % Mo, less than 0.01 wt % Ti, 0.08 wt % C, 4.98 wt % Ni, 0.10 wt % Cu, and less than 0.01 wt % Pb.
 15. The needle of claim 9 or 10 with a circular cross-section.
 16. In a method of injecting flesh of a living food animal which comprises: (a) providing an injection means comprising a tubular needle defined by at least one wall forming the tube and supported on a hub and mounted on a device for injecting a dosage of a material in an animal, wherein the needle is made of stainless steel, which is magnetizable or magnetic at a level that enables detection of the magnetism of the needle if the needle is broken off in the flesh of the living animal during the injection; and (b) injecting the living animal with the dosage using the needle, whereby when the needle breaks in the animal during the injection, the needle can be detected in the flesh of the animal upon slaughter and processing into the food.
 17. The method of claim 16 which is a hypodermic needle and wherein the material is a fluid.
 18. The method of claim 16 or 17 wherein the wall has a thickness of greater than 0.018 inch.
 19. The method of claim 18 wherein the needle has an inside diameter of about 0.046 inch.
 20. The method of claim 16 or 17 wherein the stainless steel comprises Fe and 0.01-3.0 wt % Si, less than 0.03 wt % P, 4-25 wt % Cr, 0.003-7.0 wt % Al, 0.01-1.0 Mn, 0.001-0.03 wt % S, 0.01-5.0 wt % Mo, 0.01-1.0 wt % Ti, 0.003-0.08 wt % C, 0.01-5.0 wt % Ni, 0.01-0.5 wt % Cu, less than 0.01 wt % Pb, 0.02-0.5 Bi, 0.5-1.0 wt % Nb, 0.02-1.0 wt % Zr, and 0.05-1.0 wt % V.
 21. The method of claim 20 wherein the stainless steel contains Fe and 0.36 wt % Si, 0.20 wt % P, 24.68 wt % Cr, 0.01 wt % Al, 0.90 wt % Mn, 0.009 wt % S, 1.80 wt % Mo, less than 0.01 wt % Ti, 0.08 wt % C, 4.98 wt % Ni, 0.10 wt % Cu, and less than 0.01 wt % Pb.
 22. The method of claim 16 or 17 wherein the needle has a circular cross-section.
 23. In a slaughtering method for slaughter and processing of animals for food while conveying the flesh of the animal, the improvement which comprises detecting a broken stainless steel tubular needle in the flesh, wherein the needle has at least one wall and is supported on a hub for mounting on a device for injecting a dosage of a material into an animal, wherein the needle is magnetized to a level which enables detection of the magnetism of the needle when broken off in the flesh of an animal when the animal is slaughtered and processed.
 24. The method of claim 23 which is a hypodermic needle.
 25. The method of claim 23 or 24 wherein the wall has a thickness of greater than 0.018 inch.
 26. The method of claim 25 wherein the needle has an inside diameter of about 0.046 inch.
 27. The method of claim 23 or 24 wherein the stainless steel comprises Fe and 0.01-3.0 wt % Si, less than 0.03 wt % P, 4-25 wt % Cr, 0.003-7.0 wt % Al, 0.01-1.0 Mn, 0.001-0.03 wt % S, 0.01-5.0 wt % Mo, 0.01-1.0 wt 5% Ti, 0.003-0.08 wt % C, 0.01-5.0 wt % Ni, 0.01-0.5 wt % Cu, less than 0.01 wt % Pb, 0.02-0.5 Bi, 0.5-1.0 wt % Nb, 0.02-1.0 wt % Zr, and 0.05-1.0 wt % V.
 28. The method of claim 27 wherein the stainless steel contains Fe and 0.36 wt % Si, 0.20 wt % P, 24.68 wt % Cr, 0.01 wt % Al, 0.90 wt % Mn, 0.009 wt % S, 1.80 wt % Mo, less than 0.01 wt % Ti, 0.08 wt % C, 4.98 wt % Ni, 0.10 wt % Cu, and less than 0.01 wt % Pb.
 29. The method of claim 23 or 24 wherein the animal is a swine. 